docs: async def write_message_data(self, data: bytes, timeout: NumType = None) -> None:
          """
          Encode and write email message data.
  
          Automatically quotes lines beginning with a period per RFC821.
          Lone \\\\r and \\\\n characters are converted to \\\\r\\\\n
          characters.
          """
          data = LINE_ENDINGS_REGEX.sub(b"\r\n", data)
          data = PERIOD_REGEX.sub(b"..", data)
          if not data.endswith(b"\r\n"):
              data += b"\r\n"
          data += b".\r\n"
  
          await self.write_and_drain(data, timeout=timeout)